Decoding reno-protective mechanisms in mouse Pkhd1 models: Implications for ARPKD therapeutics

解码小鼠 Pkhd1 模型中的肾脏保护机制：对 ARPKD 治疗的影响

• 批准号: 10614404
• 负责人: Ljubica Morizono Caldovic
• 金额: $ 39.27万
• 依托单位: CHILDREN'S RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10614404
• 关键词: ATP12A gene; Address; Affect; Attenuated; Autosomal Dominant Polycystic Kidney; Autosomal Recessive Polycystic Kidney; Biliary; Binding; C-terminal; Cell membrane; Compensation; Cyst; Cystic Kidney Diseases; Data; Disease; Duct (organ) structure; Engineering; Exons; Foundations; Gene Expression; Gene Family; Genes; Genetic; Genetic Models; Genetic Transcription; Human; Infant; Integral Membrane Protein; Kidney; Kidney Diseases; Liver Fibrosis; MYC Family Protein; Messenger RNA; Modeling; Mus; Muscular Dystrophies; Mutant Strains Mice; Mutation; Nuclear; Outcome; Pathogenesis; Pathway interactions; Patients; Perinatal; Phenocopy; Phenotype; Phylogenetic Analysis; Proteins; Regulation; Renal function; Research; Role; Severity of illness; Survivors; Testing; Therapeutic; Transcriptional Regulation; Translating; United States; disease phenotype; experimental study; human disease; in vivo; infancy; insight; integrated circuit; loss of function; mouse genetics; mutant; notch protein; novel; overexpression; promoter; protein protein interaction; renal epithelium; therapeutic target; trafficking

PROJECT SUMMARY There are ~1,500 patients in the United States with autosomal recessive polycystic kidney disease (ARPKD; MIM 173900), a hepatorenal fibrocystic disorder characterized by enlarged kidneys with innumerable collecting duct cysts and progressive loss of renal function. Essentially all cases of ARPKD can be attributed to mutations in PKHD1, which encodes a single-pass transmembrane protein, fibrocystin/polyductin (FPC). We currently have very little insight into the pathogenesis of human ARPKD and thus, treatment is largely supportive. Striking species-specific differences in the PKHD1/Pkhd1 renal phenotype may offer important insights into disease mechanisms. While human patients with either missense or truncating PKHD1 mutations have severe renal cystic disease, mouse Pkhd1 models with engineered truncating mutations (and presumably loss of FPC function) express minimal or no renal disease. Our preliminary studies reveal that while MYC is overexpressed in human ARPKD kidneys, Myc is not overexpressed in mouse Pkhd1 kidneys. In previous studies, we have shown that FPC undergoes Notch-like processing with cleavage of the carboxy terminus (FPC-CTD) from the plasma membrane and nuclear trafficking. Here, we demonstrate that the mouse FPC-CTD binds directly to the Myc P1 promoter and increases Myc expression. Based on these findings, we hypothesize that mouse renal epithelia can compensate for the loss of FPC-CTD function through reno-protective mechanisms and that species-specific, FPC-CTD regulation of Myc expression is central to this reno-protection. We speculate that while these mechanisms are not normally operative in human renal epithelia, they may identify new opportunities for therapeutic targeting in human ARPKD renal disease. We propose two specific aims to test our hypothesis: (1) define how the FPC-CTD regulates Myc/MYC expression in mouse and human renal epithelia and determine whether disruption of the proposed regulatory circuits is a central driver of renal cystogenesis; and (2) compare the FPC-CTD nuclear interactome in mouse and human renal epithelia and test whether differences in transcriptional targets identifies reno-protective pathways in mouse kidneys. Our studies will advance the field by sequentially addressing the transcriptional role of FPC-CTD. Specifically, we will: 1) determine mouse Pkhd1 models; how FPC-CTD related Myc transcriptional regulation contributes to reno-protection in and 2) identify putative mechanisms that allow mouse renal epithelia to compensate for the loss of FPC-CTD nuclear function. Moving forward, these data will lay the foundation for translating mouse reno-protective mechanisms into novel, therapeutic strategies that attenuate human PKHD1-related renal cystic disease.

项目摘要 美国患有常染色体隐性肾脏疾病（ARPKD）的患者约有1,500名患者； MIM 173900），一种肝纤维囊性疾病，其特征是肾脏扩大，无数收集 管道囊肿和肾功能的进行性丧失。本质上，所有ARPKD的情况都可以归因于突变 在编码单通跨膜蛋白的PKHD1中，纤维细胞蛋白/聚糖素（FPC）。我们目前有 对人ARPKD的发病机理的了解很少，因此，治疗在很大程度上是支持的。 PKHD1/PKHD1肾脏表型中引人注目的物种特异性差异可能会为您提供重要的见解 疾病机制。虽然具有识别或截短PKHD1突变的人类患者的患者严重 肾脏囊性疾病，具有工程截断突变的小​​鼠PKHD1模型（大概是FPC 功能）表达最小或没有肾脏疾病。我们的初步研究表明，虽然MYC过表达 在人类ARPKD肾脏中，MYC在鼠标PKHD1肾脏中没有过表达。在以前的研究中，我们有 表明FPC通过从羧基末端（FPC-CTD）的裂解进行类似Notch的处理。 质膜和核贩运。在这里，我们证明了鼠标FPC-CTD直接结合到 MYC P1启动子并增加MYC的表达。 根据这些发现，我们假设小鼠肾上皮可以补偿FPC-CTD的损失 通过肾脏保护机制和物种特异性的FPC-CTD调节MYC表达的功能 是这种复兴保护的核心。我们推测，尽管这些机制在人类中通常并非可行 肾上皮，他们可能会发现人类ARPKD肾脏疾病中治疗性靶向的新机会。我们 提出了两个特定的目的，以检验我们的假设：（1）定义FPC-CTD如何调节MYC/MYC表达式 在小鼠和人类肾上皮中，确定所提出的调节回路的破坏是否是 肾脏膀胱遗传学的中心驱动力； （2）比较小鼠和人类中的FPC-CTD核相互作用组 肾上皮并测试转录靶标的差异是否识别小鼠中的肾脏保护途径 肾脏。 我们的研究将通过顺序解决FPC-CTD的转录作用来推进该领域。具体来说， 我们将：1）确定 鼠标PKHD1模型； FPC-CTD与MYC的转录调节如何有助于Reno保护 2）确定允许小鼠肾上皮弥补的假定机制 FPC-CTD核功能的丧失。向前迈进，这些数据将为翻译鼠标奠定基础 肾脏保护机制变成新型的治疗策略，这些策略减弱了与人类PKHD1相关的肾脏囊性 疾病。

项目成果

Differential regulation of MYC expression by PKHD1/Pkhd1 in human and mouse kidneys: phenotypic implications for recessive polycystic kidney disease.

• DOI: 10.3389/fcell.2023.1270980
• 发表时间: 2023
• 期刊: FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY
• 影响因子: 5.5
• 作者: Harafuji, Naoe;Yang, Chaozhe;Wu, Maoqing;Thiruvengadam, Girija;Gordish-Dressman, Heather;Thompson, R. Griffin;Bell, P. Darwin;Rosenberg, Avi Z.;Dafinger, Claudia;Liebau, Max C.;Bebok, Zsuzsanna;Caldovic, Ljubica;Guay-Woodford, Lisa M.
• 通讯作者: Guay-Woodford, Lisa M.

Transcription factor Ap2b regulates the mouse autosomal recessive polycystic kidney disease genes, Pkhd1 and Cys1.

• DOI: 10.3389/fmolb.2022.946344
• 发表时间: 2022
• 期刊: Frontiers in molecular biosciences
• 影响因子: 5